1. Field of the Invention
The invention herein pertains to access plugs and particularly to threaded access plugs which may be removed to drain fluids such as oils, fuels or lubricants from equipment such as pans, sumps, transmissions, pumps and the like.
2. Description of the Prior Art and Objectives of the Invention
Equipment owners in the past have suffered damage due to access plugs such as drain plugs being improperly tightened and torqued upon replacement, such as during oil changes. Inexperienced or unskilled attendants often partially replace an access plug, and forget to torque the plug to prevent it from loosening due to the vibrational forces created as the equipment is operated. Once an access plug sufficiently loosens, oil leakage occurs which left untightened over a period of time can cause engine failure. In certain equipment other fluid-containing plugs are also necessarily torqued to prevent inadvertent vibrational removal.
Various types of compression members and expandable plugs have been devised in the past to prevent inadvertent removal as by vibration, some of which require special tools, washers or steps to tighten, such as seen in U.S. Pat. Nos. 4,231,544, 4,986,502 and 5,184,698.
While such prior art devices have been somewhat successful in certain instances, there remains a need for a simple, inexpensive means for preventing inadvertent plug removal by the forces created by vibration during equipment operation.
Thus, with the disadvantages and complexities of prior art access plugs, the present invention was conceived and of its objectives is to provide a simple, inexpensive threaded access plug which will prevent inadvertent vibrational removal or excessive loosening, even if improperly tightened.
It is another objective of the present invention to provide an access plug which can be used in equipment oil pans or otherwise to securely contain fluid.
It is also an objective of the present invention to provide an access plug, which in the preferred form, includes a filler formed from a dense, heavy metal such as lead.
It is yet another objective of the present invention to provide a weight imbalanced access plug which can be easily substituted for a conventional plug yet which will prevent inadvertent rotational loosening movement due to its weight imbalance.
It is also an objective of the present invention to provide an access plug which can be easily used without special training or tools.
Various other objectives and advantages of the present invention will become apparent to those skilled in the art as a more detailed description is set forth below.